Importance of mutations of the suppressor gene TP 53 and increased accumulation of protein p53 in the nuclei of tumour cells in the pathogenesis of carcinoid tumours of the gastrointestinal tract was not explained unequivocally so far. The absence of impaired expression of p53 in the majority of carcinoid tumours may be associated with a higher grade of differentiation of tumour cells and may be one of the factors participating in the unequal biological behaviour of carcinoids located in different parts of the gastrointestinal tract. In the submitted study the authors analyzed 49 bioptic specimens of carcinoids obtained from different portions of the gastrointestinal tract from a total of 44 patients. Tissue specimens were processed by the common paraffin technique and basic histological examinations were made. Subsequently immunohistological detection of p53 protein was implemented in paraffin sections by means of the antibody clone DO-7(DAKO). The authors found in their group a typical intranuclear positivity of p53 in eight (16.3%) tumours. Only two of these positive tumours were evaluated as typical carcinoids, the remaining six tumours were atypical carcinoids. p53 positive tumour cells had in the majority more marked cytological irregularities and had a higher proliferating activity. The results of the investigation support the view that increased accumulation of protein p53 in nuclei of tumour cells may play a significant role in the biological behaviour of carcinoids of the gastrointestinal tract, in particular in atypical tumours. Evidence of protein p53 in tumour cells can be considered an adverse prognostic indicator.

        Key words: gastrointestinal carcinoids – p53 –imm unohistological detection –biolo gical properties of tumours